This proposal requests funds to purchase a Nd:YAG pulsed tunable dye laser system for shared use by three NIH-supported investigators. This instrumentation is not currently available at the University of California, Riverside. The laser system will serve as a general purpose excitation source for resonance Raman, two-photon and desorption/ionization mass spectroscopy of biomolecules. The requested instrument will be installed in the Chemistry Department at the University of California, Riverside and operated under the supervision of the Principal Investigator who will head an advisory group comprised of the three users. The dye laser system will open new areas for spectroscopic study when interfaced with the existing resources of the user group.